南极海冰的生长消融与全球气候变化密切相关,而海冰上覆盖的积雪会对海冰的生长消融产生较大的影响.利用南极中山站附近海冰上的GPS数据,采用GNSS-IR(GNSS interferometric reflectometry)技术对海冰上覆积雪深度进行反演.首先,采用最小二乘谐波分析(least-squares harmonic estimation,LS-HE)方法提取反射信号的主波峰,计算反射面到天线相位中心的距离;其次,采用DBSCAN(density-based spatial clustering of applications with noise)聚类算法对反演结果进行质量控制;最后,利用现场实测雪深数据对反演结果进行了验证,平均偏差为-0.01 m,RMSE为0.012 m,表明GNSS-IR技术能够有效反演海冰表面积雪深度.
Abstract
The growth and melting of Antarctic sea ice are closely related to global environmental changes,and the snow covered on the sea ice will have a large impact on the growth of sea ice. In this paper,GNSS-IR is used to analyze GPS da-ta on sea ice near Zhongshan Station in Antarctica in order to invert the depth of snow overlying the sea ice. First,the least-squares harmonic estimation method is used to extract the main wave peak of the reflected signal,which is used to calcu-late the distance from the reflecting surface to the antenna phase center. Then,the DBSCAN clustering algorithm is used to quality control the inversion results. Finally,the in-version results are verified by the actual snow depth data in the field. The average deviation after clustering is about-0.01 m,and the RMSE is about 0.012 m,indicating that the GNSS-IR technique can effectively invert the snow depth on the surface of sea ice.
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